The prior art contains many examples of devices intended to facilitate the task of mating a syringe to a vial for the purpose of extracting medicament from the vial. U.S. Pat. No. 5,240,047 issued to the present inventor is one example of such a device. U.S. Pat. No. 5,247,972 is another example. Both patents list several patents disclosing related devices cited during the prosecution of the patents. However, no prior art device possesses the same advantages as the present invention. For example, in order to use the devices disclosed in U.S. Pat. Nos. 5,240,047 and 5,247,972 the cap on the needle must be removed before the syringe can be inserted into either device. Handling the syringe with an exposed needle increases the risk of injury to the user and also damage to the needle itself. The device disclosed in U.S. Pat. No. 5,247,972 is also more expensive to produce and more difficult to use than the present invention.
The present invention is a continuation of the effort to provide devices that are safer and easier to use especially for untrained individuals who inject medications to themselves or family members. Greater economy and simplicity are also desirable goals especially in the face of rising health care costs. The present invention differs from the invention covered in my above-identified parent application primarily in it applicability to syringes that have a large diameter barrel. The present device will fit over the needle cap on such a syringe and therefore can be used with such commercially available syringes without changing the syringes. The device of my parent application acts as a substitute for the needle cap for syringes where the barrel of the syringe has a diameter almost equal to that of the needle cap. Both the devices of my parent application and the present application are superior to the device claimed in my U.S. Pat. No. 5,240,047 in limiting the user's exposure to the needle until the syringe is filled and ready for injection.